1. <January 2002>
doc.: IEEE <02/139r0>
March, 2008
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Reliable Performance Analysis of ]
Date Submitted: [March 16, 2008]
Source: [Kyungsup Kwak1,]
Company: [Inha University1]
Address: [ 6-141B, Inha University, 253 Yonghyun-dong, Nam-gu, Incheon, , Republic of Korea]1
Voice: [], FAX: [], (other contributors are listed in “Contributors” slides)]
Re: []
Abstract: [????]
Purpose: [To be considered in IEEE c standard]
Notice: This document has been prepared to assist the IEEE P It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.
Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P
Inha Univ.
Chuck Brabenac, Intel Labs

2. Contributors Name E-mail Affiliation Kyungsup Kwak kskwak@inha.ac.kr
March, 2008
Contributors
Name
Affiliation
Kyungsup Kwak
Inha University
Inha Univ.

3. Overview Backgrounds Objects(Goal)
March, 2008
Overview
Backgrounds
Start at Question of last contribution
Objects(Goal)
Memory buffer size in receiver is very important.
Superframe size is related to the buffer size.
The application of uncompressed video transmission is delay sensitive and requires constant bandwidth allocation.
Allocating Bandwidth below the required throughput causes service failure.
So, PHY-SAP payload bit rate is key parameters
Simulation and analytical results show that we can find superframe size and payload length according to the requirements (data rate, delay and memory usage).
Propose a sizing procedure to find a proper superframe size according to the requirements of uncompressed video transmission.
Inha Univ.

4. 802.15.3c Performance Metrics Throughput End-to-End Delay
March, 2008
c Performance Metrics
Throughput
measured in terms of bits per second, is the amount of data delivered successfully by the peer MAC-SAP.
End-to-End Delay
measured in terms of second, is the amount of time taken for a MAC SDU to be transferred from the MAC-SAP of the transmitter to the peer MAC-SAP of the receiver.
Memory usage (MAC)
Memory usage represent the minimum buffer size required for continuous video representation
Inha Univ.

5. Considering Superframe Structure
March, 2008
Considering Superframe Structure
Inha Univ.

6. Preamble and PLCP Header
March, 2008
Parameters Assumed
Use common mode beacon to 47.8 Mbps
Assume error free PHY channel
Set video traffic to CBR traffic mode
One MAC SDU is composed of data bits transmitted in one horizontal line.
Assume no buffer delay due to higher data rate
Assume no propagation delay due to short distance ( < 10 meter)
Consider transmission delay in terms of Overhead & Payload Size
Simulate in the NS-2
Parameters
Value
Superframe Size
1 msec ~ 64 msec
Beacon Interval ??
CAP Duration
0 / 200 usec
Guard Time
0.02 usec
SIFS
2.5 usec
Preamble and PLCP Header
8.157 usec
PHY-SAP Rate
1632, 2000 Mbps
Payload Size
2 KB ~ 64 KB
Sub-header Size
4 Bytes
ACK Policy
N/A
Aggregation Method
Applied
MAC-SDU Size
5.5 KB
Inha Univ.

7. March, 2008
MAC Throughput
Superframe size = 16 ms, Preferred payload size = 5.5k, no aggregation
Inha Univ.

8. Conclusions RT traffic (video streaming) NRT traffic (data transfer)
March, 2008
Conclusions
RT traffic (video streaming)
Constant bandwidth
Stringent timing requirement
No ACK policy is preferred
Near error-free channel
Directly discard broken frames
Retransmission is useless
NRT traffic (data transfer)
ACK and retransmission is needed to correct frame errors
Imm-ACK has the lowest performance
Dly-ACK can improve throughput
Number of un-acked frames should not be small
On the other hand, delay jitter may be larger.
Inha Univ.

9. Procedure of Sizing the Superframe Size
March, 2008
Procedure of Sizing the Superframe Size
Inha Univ.

10. Consideration of Buffer and Its Utilization
March, 2008
Consideration of Buffer and Its Utilization
The buffer limit would be one of capability parameters of the device. It shows how many data can be temporarily stored in the device for the smoothly video representation.
The occupation of this kind of buffer is related with data rate, and superframe size, etc.
i.e. Minimal buffer required = data rate * superframe size
Given a buffer limit, however, we would want to fully utilize it in order to achieve better performance.
It is suggested that within the buffer limit of the device, select as large as possible superframe size in order to increase the CTAP efficiency additionally and reduce the delay.
Inha Univ.

11. March, 2008
Conclusions
With this comparison we can propose the minimum requirement on PHY-SAP rate to transfer uncompressed video traffic.
To improve the transmission efficiency, the aggregation should be used, which results in larger payload length. However, the transmission delay is correspondingly increased.
By considering the expense of beacon period and CAP, the channel time for each flow and relevant superframe size should be lengthened. However, there would be more buffered data and then more memory would be required.
The superframe size should be set to relative bigger to achieve proper effective throughput, when the PHY-SAP rate is low. On the other hand, for the high PHY-SAP rate, the superframe size could be shortened to lower the memory requirement. In both cases, the delay should be considered in the selection of superframe size and payload length if the QoS is emphasized.
Our proposal provide the baseline for finding superframe size in terms of delay requirement and memory usage.
Inha Univ.

12. March, 2008
Appendix
Inha Univ.

13. Delay and Throughput Definitions
March, 2008
Delay and Throughput Definitions
Maximum achievable throughput represents the maximum MAC capacity. In real world scenario, we can’t achieve the maximum achievable throughput because of several reasons like MSDU size, collision , etc.
Minimum Delay bound is the minimum transmission time required by a MAC MSDU to reach destination MAC layer from Source MAC layer
Inha Univ.

14. Parameters on Video Resolution
March, 2008
Parameters on Video Resolution
Formant
V Freq
HRES
VRES
DE_CNT
DE_LIN
Rate 24bit
Rate 20bit
Hsync (sec)
Vsync (sec)
1080i 30
2200
562/ 563
1920
1080
5760
4800
E-06 /
1080p
1125 60
E-06
Inha Univ.